1. Field of the Invention
The present invention relates to an optical monitoring apparatus for use in a wavelength division multiplexing network, and more particularly to an optical monitoring apparatus based on the scanning of the gain profile of erbium-doped fiber amplifiers (EDFA) and applied in a wavelength division multiplexing network.
2. Description of the Prior Art
The wavelength division multiplexing (WDM) technology has been widely used to amplify bandwidth of an optical fiber network. In addition, such technology helps to enhance optical properties such as quality of the optical signals, channel characteristics and systematic monitoring performance, etc. In the prior art, spectrometers, wave measuring instruments, filters, tunable filters or Faber-Perot filters are employed to monitor optical signals. Theses instruments and the measuring ways using them are relatively expensive. Recently, some new technologies were developed to solve the problems. For example, these technologies comprise introducing a tracing wave to the system for a purpose of identifying wave channels or monitoring power thereof, monitoring semiconductor optical amplifiers or semiconductor laser diodes at the transporting locations of different wavelengths, or connecting a plurality of fiber Bragg grating (FBG) as wave channels of an optical sampling system. However, above-described prior art apparatuses are not perfect designs and have still many disadvantages to be solved. These apparatus are well known to a person skilled in the art and need not be further described in detail herein.
In views of the above-described disadvantages resulted from the conventional apparatuses, the applicant keeps on carving unflaggingly to develop a WDM-network optical monitoring apparatus according to the present invention through wholehearted experience and research.